The present inventions relates to a lamp socket for attaching a lamp such as a car headlight thereto.
In these years, because of importance of safety in a car headlight, a discharge lamp, which has higher luminance, lower power consumption, and longer life in comparison with a conventional halogen lamp, has been used. In the discharge lamp, it is necessary to generate a very high voltage pulse, which is as high as about 25,000 V, upon startup. Generally, the high-voltage pulse is generated using a transformer provided in a lamp socket in a discharge lamp. However, the high-voltage pulse generated with the transformer adversely affects peripheral devices. Accordingly, there are various configurations proposed in order to improve a voltage resistance of a lamp socket.
Patent Reference 1 and Patent Reference 2 have disclosed conventional lamp sockets having the above-described configurations. In the lamp socket disclosed in Patent Reference 1, a transformer itself is integrally molded with an outer package, and an outer package is further integrally molded with the transformer, thereby preventing adverse effects due to the high-voltage pulse generated with the transformer on peripheral devices.
In the lamp socket disclosed in Patent Reference 2, a circuit board, on which electronic components except a transformer are mounted, is molded with a resin first. Then, the transformer is molded in a specified position of a housing case using an epoxy resin (a thermoset synthetic resin), and the circuit board having the transformer molded therein is attached to the housing case, thereby producing the lamp socket.
Patent Reference 1: Japanese Patent Publication No. 2002-216534A
Patent Reference 2: Japanese Patent Publication No. 2002-289313A
In the conventional configurations described above, when a resin is integrally molded, a crack may be generated in the resin under a severe temperature condition. In addition, it is necessary to provide a special apparatus for performing the integral molding twice and an additional assembling step, thereby increasing a manufacturing cost and reducing productivity. Furthermore, the manufacturing cost further increases due to the secondary molding.
Especially, in the configuration disclosed in Patent Reference 2, the transformer is not mounted until the electronic components except the transformer are integrally mounted on the circuit board. Accordingly, it is difficult to assemble the circuit board and the transformer at the same time, thereby increasing a manufacturing cost and reducing productivity.
In view of the problems described above, an object of the present invention is to provide a lamp socket capable of solving the problems of the conventional lamp socket. In the present invention, it is possible to easily manufacture the lamp socket without the integral molding and reduce a manufacturing space thereof.
Further objects of the invention will be apparent from the following description of the invention.